Stoker



May 16, 1944.

F. J. PALMER STOKER Original Filed Aug. 28, 1939 m m a m 4 p; 2 W a m a a w Patented May 16, 1944 UNITED STATES FATE. NT OFF 'l'C'E STOKER Floyd J. Palmer, Cleveland, Ohio Original application August 28, 1939, Serial No. 292,164. Divided and this application March 13, 1941, Serial No. 383,097

2 Claims.

This application is a division of my copending application Ser. No. 292,164, filed August 28, 1939.

My invention relates to stokers, and particularly to stokers of the type in which the fuel is fed into the lower portion of a retort by means of a generally horizontal feed-screw disposed in the feed-tube. It is the primary object of my invention to prevent packing of fuel against the rear wall of the retort as the result of the action of the feed-screw and to insure positively an upward feeding and uniform distribution of fuel within the retort. Another object of my invention is to eliminate packing of fuel within the feed-tube as the result of resistance at the base of the retort.

Among other objects of my invention are to reduce degradation of the coal and to correct for any segregation according to particle size which occurs as the coal is fed through the feedtube.

In carrying out my invention I form the feedscrew, within the lower portion of the retort, with one or more pockets having sidewalls which diverge outwardly in the direction of feed-screw rotation, one side wall of each of such pockets conveniently being formed as a continuation of the helical flight of the feed-screw. Such pocket or pockets are centered approximately with reference to the axis of the retort; and as the feedscrew rotates, the action of the angularly dis- 3 posed pocket-walls positively forces the fuel laterally of the feed-screw and upwardly into the retort.

The accompanying drawing illustrates my invention: Fig. l is a vertical section through the lower portion of a furnace showing my stoker in place therein; and Fig. 2 is an enlarged frag mental elevation of the inner end of the feed screw.

The furnace illustrated in the drawing has a lower portion 10 in which the stoker is mounted and an upper portion or combustion chamber. The inner end of the stoker mechanism is supported from the floor l2 of the furnace by means including a base member l3 and a screw M, the latter having its upper end received in a recess in the retort and its lower end screw-threadedly mounted in the base member l3. By adjusting the screw M, the retort may be disposed at the desired height.

The stoker, which as a whole, is more fully described in my aforesaid copending application, includes an upwardly opening retort l5, at least the lower portion of which is desirably in the form of a casting having a laterally projectin neck IS in which the inner end of the fuel-feed tube 11 is received. Within the fuel-feed tube I1 I mount a feed-screw consisting of a central shaft l8 and a helical flight l9, the inner end of the shaft 18 conveniently being supported by a suitable bearing 20 in the rear wall of the retortthroat 15.

The helical flight l9 terminates short of the rear wall of the retort l5, and opposite its end I provide on the shaft l8 a helically disposed vane 25 which is of opposite hand to the flight I9. The inner end of the flight l9 and the vane 25 co-operate to form a pocket 26 the side walls of which diverge in the direction of rotation of the feed-screw. As the screw rotates, the converging side walls of the pocket 26 exert on the fuel a pressure which is reflected in a positive tendency of the fuel to rise in the retort. I have found it advantageous to leave the narrow end 21 of the pocket 26 open, the width of the opening 2'! being of the order of the diameter of the largest fuel particles to be fed through the tube i1. By this expedient I am enabled to prevent fuel particles of relatively large size from becoming wedged in the narrow end of the pocket 26 and from jamming against the side walls of the retort-throat.

While one of the pockets 26 will produce a very noticeable and positive upward feeding of fuel in the retort, I find it desirable to provide the feedscrew with two such pockets. Accordingly, I have shown in Figs. 1 and 2 a helically disposed vane 28, which is mounted on the opposite side of the shaft from the vane 25, and a second helically disposed vane 29 mounted on the shaft is in opposed relation to the vane 28. The vane 28 may be, in effect, a continuation of the flight l9, and is of the same hand as the flight IS. The vane 29 is of opposite hand and eo-operates with the vane 28 to form a second feed pocket 30, the action of which on the fuel is substantially the same as that of the pocket 26. The pockets 26 and 30 are disposed approximately symmetrically relative to the axis of the retort, so that their action on the fuel will be centered relatively to the retort and will result in an even distribution of fuel inthe bowl.

I claim as my invention:

1. In a stoker, a retort, a horizontal fuel-feed tube communicating with said retort near the bottom thereof, and a feed screw in said feed tube, said feed screw extending into the lower portion of the retort and being there provided with a plurality of axially overlapping and angularly spaced pockets positioned to receive fuel fed into said retort by said feed screw, each of said pockets having opposed helical side walls of opposit hand diverging from each other in the direction of screw rotation.

2. In a stoker, a retort, a horizontal fuel-feed tube communicating with said retort near the bottom thereof, and a feed screw in said feed tube, said feedscrew extending into the lower portion of the retort and being there provided with a plurality of axially overlapping and angularly spaced pockets positioned to receive fuel fed into said retort by said feed screw, each of said pockets having opposed side walls of opposite hand diverging from each other in the direction of screw rotation.

- FLOYD J. PALMER. 

